Cell Metabolism

Metabolism

The sum of all chemical reactions occurring in a cell

Energy metabolism

Reactions involved in energy storage and use

Direction of reaction

uForward (reactants transformed into products)

uReverse (products transformed into reactants)

uReactions actually bidirectional

Metabolic Reactions: Catabolic

breakdown of larger molecules into smaller ones

Metabolic Reactions: Anabolic

usynthesis of larger molecules from smaller reactants

Types of Reactions: Hydrolysis and condensation

water used to break bonds, or water formed because of reaction

Types of Reactions: Phosphorylation and dephosphorylation

phosphates added or removed from substrates

Types of Reactions: Oxidation-reduction

electrons added or removed from substrates

Energy

capacity to do work

Kinetic energy

associated with motion

• uThermal, electromagnetic, electrical

Potential energy

stored energy

• uChemical, mechanical, nuclear, gravitational

First Law thermos

energy in universe (a closed system) is constant

uEnergy can be neither created nor destroyed

uThe human body is an open system ® exchanges matter and energy with surrounding